We are analyzing the dna sequences in coding regions of certain monkey genes to test the hypothesis that mutation frequencies in these regions are similar to frequencies observed in human populations. If the hypothesis is confirmed, it would be feasible (and cost-effective) to develop primate models of human diseases by breeding primates carrying naturally occurring mutations.[unreadable] Small amounts of blood are obtained during the routine, periodic physical examinations of animals and genomic DNA is purified from the samples and analyzed. We have begun screening the DNA using single stranded conformation polymorphisms (SSCP) analysis. In this analysis, a fragment of DNA (typically an exon from genomic DNA) is amplified via polymerase chain reaction (pcr) in the presence of radiolabeled nucleotides, denatured, and run on a non-denaturing gel. When samples from many individuals are run side by side, all individuals having identical DNA sequences in each of their two chromosomes form a distinctive pattern. Any departure from this pattern, including single base pair differences, can be detected with close to 100% fidelity. We have purified dna from 330 rhesus and 12 cynomolgous monkeys. We are in the process of designing and testing primers for regions of interest, based on homologies with known human sequences. An initial analysis of two exons in 160 rhesus macaques has revealed several sequence variations. Direct sequencing of three variants has indicated that all of them are polymorphisms. This is consistent with our initial calculations, which suggested that disease causing mutations would occur at much lower frequencies. The polymorphisms may prove to be useful for tracking genetic variation and establishing geographic origins of captive primates. Crprc administration:2a2 drb.